Saviuk's professional career began in 1977 at DC Comics, where he illustrated such titles as Green Lantern, The Flash and Superman.[6] Saviuk's first work for DC was a one-page story titled "The Victim!" in House of Mystery #255 (Nov.-Dec. 1977).[7] His first full work for the company, Green Lantern #100 (Jan. 1978), introduced an updated version of the Air Wave character.[8] Saviuk drew The Flash #275 (July 1979) wherein the title character's wife, Iris West Allen was killed.[9]

In the early 1980s, Saviuk was the regular backup feature artist on Action Comics, where he drew the exploits of Air Wave, Aquaman and the Atom in collaboration with writer Bob Rozakis. Rozakis stated in a 2014 interview that "I don't recall how we ended up with the three of them. It may have simply been that all three had names that began with 'A' and it was a backup in Action Comics".[10] Saviuk frequently drew the "Whatever Happened to...?" backup feature in DC Comics Presents.[11] He and writer E. Nelson Bridwell introduced the Global Guardians in DC Comics Presents #46 (June 1982).[12]

In 1986, Saviuk moved to Marvel Comics, where he eventually established himself as a key Spider-Man artist with a seven-year run on Web of Spider-Man (issues #35-116). In 1989, he drew the The Amazing Spider-Man: Parallel Lives graphic novel.[13] From 1994–1996, Saviuk worked on the series Spider-Man Adventures (later retitled The Adventures of Spider-Man).[14] Since 1997, Saviuk has drawn The Amazing Spider-Man Sunday newspaper comic strip,[14] written by Stan Lee; since 2003, he has inked the daily Spider-Man strip, pencilled by Lee's brother Larry Lieber, and pencilled the Sunday page of the same, inked by Joe Sinnott.[3]